Letter to the Editor From Devgan and Mayilvaganan: “Natural History and Predictive Factors of Outcome in Medullary Thyroid Microcarcinoma” Free

We read the article “Natural History and Predictive Factors of Outcome in Medullary Thyroid Microcarcinoma” with great interest and discussed it in our departmental journal club.

We congratulate the authors for the discussion on this very pertinent study on the issue of micro–medullary thyroid microcarcinoma (micro-MTC) which has been a matter of great debate even today.

The existing literature regarding micro-MTC is limited and variable, resulting in controversy regarding the appropriate extent of surgical treatment, especially regarding a size threshold for cancers, with larger than 5 mm suggested as a cutoff for clinically relevant cancers (1). Recent studies have demonstrated lower, but not insignificant, rates of nodal involvement in patients with tumors smaller than 5 mm, suggesting that this size cutoff has limitations when applied to practice (2).

We have a few comments and queries to make which may interest future readers:

1. This study demonstrated the utility of tumor grade in predicting outcomes in micro-MTC and we agree that the use of grading in micro-MTC represents a potential tool to assist in determining the appropriate extent of surgery and follow-up following the identification of sporadic micro-MTC.

2. For patients with a nonincidental diagnosis of micro-MTC (n = 5), how was the diagnosis of micro-MTC suspected/arrived at (since usually nodules of less than 1 cm are not routinely subjected to fine-needle aspiration biopsy)?

3. Was preoperative calcitonin done in all nonincidental cases of micro-MTC, and if yes, was there any correlation between the size of the tumor and calcitonin levels?

4. For patients with incidental diagnosis of micro-MTC who underwent hemithyroidectomy without completion (n = 4), what was the average duration of follow-up of these patients and was there any evidence of structural or biochemical recurrence in these patients?

Thanks for commenting on these issues.

Yuvraj Devgan

Sabaretnam Mayilvaganan

Disclosures

Authors have no conflicts of interest to disclose.

References

Abbreviations

 
• FNAB

  fine-needle aspiration biopsy

 
• MTC

  medullary thyroid carcinoma